Abbreviation of Control Program for Microcomputers. Created by Digital Research Corporation, CP/M was one of the first 8-bit operating systems for personal computers. However, Digital Research Corporation made a critical strategic error by not agreeing to produce an operating system for the first IBM PC. According to the folklore, the president of Digital Research was flying his airplane when IBM came to call. IBM marched out and never looked back.

Instead, IBM turned to Microsoft Corporation, which developed MS-DOS based on version 2.2 of CP/M. By the mid 1980s, MS-DOS had become the standard operating system for IBM-compatible personal computers. CP/M is now obsolete.